Auto theft prevention device

ABSTRACT

A security system for motor vehicle ignition or starting circuits wherein a lock switch unit is connected between essential circuit elements such as the primary coil and the distributor. The system has a special provision for the defeating attempts to bypass the lock switch by cutting the conductors to and from the switch and shorting the circuit between the essential circuit elements. This is accomplished by means of a cable extending between the lock switch unit and an essential circuit element and comprising a plurality (e.g., 20 or more) of discrete identical insulated conductors. A first group of these conductors is connected between the switch unit and one essential circuit element, a second group between the switch unit and another essential circuit element and a third group is grounded at one end. If the cable is cut through by a thief, he would be unable to distinguish the conductors of the three groups and would thus be frustrated in an attempt to bypass or short circuit the lock switch.

United States Patent Tsevdos et a]. f

[ AUTO THEFT PREVENTION DEVICE [76] Inventors: Theodore L. Tsevdos,28900 Gates Mills Blvd., Pepper Pike, Ohio 44124; Nicholas L. Tsevdos,1031 W. Hill Mill Dr., Highland Heights, Ohio 44143; Milton D.Tenenbaum, 3085 Lincoln Heights, Cleveland Heights, Ohio 441 18 [22]Filed: May 20, 1974 [21] Appl. No.: 471,557

Primary ExaminerHerman Hohauser Attorney, Agent, or FirmBosworth,Sessions &

McCoy [451 July 1,1975

[57] ABSTRACT A security system for motor vehicle ignition or startingcircuits wherein a lock switch unit is connected between essentialcircuit elements such as the primary coil and the distributor. Thesystem has a special provision for the defeating attempts to bypass thelock switch by cutting the conductors to and from the switch andshorting the circuit between the essential circuit elements. This isaccomplished by means of a cable extending between the lock switch unitand an essential circuit element and comprising a plurality (e.g., 20 ormore) of discrete identical insulated conductors. A first group of theseconductors is connected between the switch unit and one essentialcircuit element, a second group between the switch unit and anotheressential circuit element and a third group is grounded at one end. Ifthe cable is cut through by a thief, he would be unable to distinguishthe conductors of the three groups and would thus be frustrated in anattempt to bypass or short circuit the lock switch.

6 Claims, 7 Drawing Figures SHEET AUTO THEFT PREVENTION DEVICEBACKGROUND OF THE INVENTION This invention relates to anti-theft systemsfor motor vehicles and especially to systems for disabling a motorvehicle by securing an essential electrical circuit, such as the primaryignition circuit or starter circuit, against unauthorized activation.More particularly, the invention relates to an improvement in lockswitch type antitheft devices that disable the primary ignition circuitor starter circuit. Such lock switch type anti-theft devices aredisclosed in U.S. Pat. Nos. 3,675,035; 3,697,945 and 3,745,27l.

The anti-theft devices of these patents are intended to prevent jumpingof the ignition circuit or, in other words, bypassing the key-operatedlock switch, by connecting a separate jumper" across the input andoutput terminals of the ignition switch. The device includes acombination lock switch unit connected between the distributor andprimary coil using two conductors, at least one of which is located inan armored conduit.

While this type of device discourages most auto thieves, occasionally amore sophisticated thief with special tools and using considerable forcewill break the connection between the armored conduit and the lockswitch housing. Then the two conductors from the distributor and primarycoil respectively may be connected, the key lock ignition switch jumpedand the car started and stolen.

While many techniques have been developed to defeat attempts to bypassor short circuit a lock switch, their effectiveness only endures until anew technique can be developed by professional thieves. Mostprofessional car thieves prefer to work inside a car to be stolen ratherthan in the engine compartment with the hood raised. This is probablydue to the reduced probability of suspicion or detection. In any event,it is most important that any portion of an anti-theft device locatedinside the passenger compartment of a vehicle be especially protectedagainst tampering by thieves. The theft prevention device of the presentinvention substantially increases the security of a lock switch unit ofthe type described, particularly as to those parts within the vehicle,and affords other features and advantages heretofore not obtainable.

SUMMARY OF THE INVENTION It is among the objects of the invention todefeat attempts to steal automobiles containing a lock switch mechanismin the motor vehicle ignition circuit or starter circuit.

Another object is to protect a security system in the ignition circuitor starter circuit of an automobile against unauthorized tampering byprospective thieves.

Still another object is to provide a security system for the primaryignition circuit or starter circuit of an automotive vehicle, that makesit difficult, if not impossible, for a thief to jump the particularcircuit by connecting a separate jumper wire between essential circuitelements.

These and other objects are accomplished by means of an improvedautomobile security system of the type that includes a lock switchassembly electrically connected between essential circuit elements suchas the primary coil and distributor of the engine ignition circuit. Theimprovement embodying the invention comprises a cable consisting of aplurality of discrete identical insulated conductors including a firstgroup con nected between the lock switch and the primary coil, forexample, a second group connected between the lock switch and thedistributor, for example, and a third group connected to ground. If thecable is cut by a prospective thief, the conductors of the groups areindistinguishable from one another and thus inhibit the properinterconnection of the severed conductors to afford sufficicnt currentcarrying capacity to enable circuit elements to function and provide aground if the conductors are improperly connected.

While the lock switch assembly of the invention may be used inassociation with different electrical circuits for the vehicle engine,such as the starter circuit, it will be illustrated and described onlyin connection with the engine ignition circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic diagram of amotor vehicle electrical circuit including a combination type electricallock switch and an improved cable construction embodying the invention;

FIG. 2 is a perspective view of the automobile security unit illustratedschematically in FIG. 1 and showing the cable construction embodying theinvention;

FIG. 3 is a vertical section on an enlarged scale with parts broken awayand including a fragmentary sectional view of a portion of the vehicledistributor;

FIG. 4 is a sectional view on an enlarged scale taken on the line 44 ofFIG. 2;

FIG. 5 is a perspective cross-sectional view of the cable of FIGS. I and2;

FIG. 6 is a perspective view on an enlarged scale of one of the discreteindividual insulated conductors of the cable of FIG. 5; and

FIG. 7 is a schematic diagram illustrating the 24 individual discreteconductors of the cable of FIG. 5 after they have been broken such as bycutting through the cable, and illustrating the futility of attemptingto interconnect the individual discrete conductors to bypass the lockswitch.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly tothe drawings. FIG. I shows certain electrical circuits for a motorvehicle including an ignition circuit having a combination type lockswitch 10 of the type described in U.S. Pat. No. 3,697,945, interposedbetween the coil 11 and the distributor I2. The various circuits areactivated by a keyoperated ignition lock switch 13 connected in seriesbetween the battery 14 and the various other circuits.

The switch 13 has three movable contacts 13a, 13b and 13c, one of which,energizes a starter circuit including a starter solenoid l5 and thestarter 16. Another movable contact l3b energizes certain accessorycircuits such as, for example, a radio, heater blower, etc. Anothermovable contact 130 energizes the ignition circuit including the coil 11and the distributor [2. The circuit extends through the primary coil 17and from the negative terminal of the primary coil 17 to the combinationlock switch 10. The secondary coil 18 has a central terminal 19 with ahigh tension lead 21 connecting the terminal 19 to the rotor 22 of thedistributor I2.

The combination lock switch unit has a casing 30 that contains threerotary switch units 31, 32 and 33. Each unit has a switch shaft 34 witha knurled front end that receives a dial knob 36 secured to the frontend 35 by a set screw 37. The front end 35 of each shaft 34 extendsthrough a control panel 38 on the front end of the casing 30 and eachdial knob 36 has indicia thereon that may be used with related indiciamarked on the control panel 38. Each of the shafts 34 is journaled in abushing integral with the casing 30 and extends through a printedcircuit board 45 located within the casing 30. The circuit board hasimprinted thereon (FIG. 4) an ignition-circuit closing conductor pattern49.

Each switch shaft 34 carries a rotary contact carrier 50 with a contactarm 51, and each contact carrier 50 is electrically connected to theignition-circuit closing conductor pattern 49. The contact carrier 50has a raised dimple 53 (FIG. 4) that engages a stationary contact disc54 imprinted on the circuit board 45, the disc 54 being electricallyconnected to the circuit closing conductor pattern 49.

Accordingly. whenever the contact arm 51 of one of the rotary switchunits 31, 32 or 33 is in the correct predetermined position and incontact with the respective portion of the circuit closing conductorpattern 49, the ignition circuit between the coil 11 and the distributor12 will be completed. It will be noted that each of the rotary switchunits 31, 32 and 33 has only one position in which its respective rotarycontact carrier 50 is electrically connected to the respective portionof the circuit closing conductor pattern 49.

As indicated above in the Background Of The Invention, an automobilesecurity system of the type to which the present invention relatesrequires that certain conductors extend from the lock switch unit 10,through the vehicle fire wall to the engine compartment. It isespecially important that all portions of conductors located within thepassenger compartment be secured against tampering so as to defeat anyattempt by a thief located within the passenger compartment to bypassthe switch system. In the present instance, these conductors areconfined in an armored conduit 55 that extends from a tubular connectorelbow 56 securely anchored to the housing for the distributor 12, to afitting 57 securely anchored to the casing 30 of the lock switch unit10. The respective end of the armored conduit 55 is welded or otherwisesecurely fastened to the connector 57 which has a threaded end extendingthrough the wall of the casing 30 and anchored thereto by a nut 58.

Thus, the armored conduit 55 inhibits any attempt to obtain access tothe conductors associated with the lock switch unit 10 except accesswhich might be obtained with special equipment such as a hack saw or thelike. The unique construction of the conductors embodied in the presentinvention. however, further impedes attempts to defeat the lock switch10 even though a thief may cut through the armored conduit 55.

In accordance with the invention, a cable assembly is located within thearmored conduit 55, the cable comprising a plastic insulating sleeve 59with a plurality (in this instance 24) of discrete insulated conductorslocated therein. In the present instance the conductors comprise No. 26size copper wire insulated with a resin coating The resin may be anepoxy compound, for example, as in the case of magnet wire or wire usedin the winding of magnet coils. The conductors include (FIGS. 1 and 7) afirst group of seven wires 60 connected between the conductor pattern 49on the printed circuit to a junction located within the fitting 56, asecond group of seven wires 61 electrically connected between one of thestationary contacts 52 and the distributor 12, and a third group of tenground wires 62 which are bundled and dead-ended within the casing 30 ofthe lock switch unit 10 and connected to ground at the connector 56 onthe distributor 12. The first and second groups preferably are of anequal number. The wires 60 and 61 are wrapped around the interior of thecasing 30 (FIGS. 1 and 4) in order to assure that they cannot be easilypulled out of the lock switch unit 10. The wrapped portions of the wiresare embedded or potted in a suitable potting compound such as Emerson &Cummings Epic resin, which is an epoxy resin. Phenolic resins, polyesterresins or other electrical potting compounds may be used instead of theaforesaid epoxy resin as will be apparent to those skilled in the art.In this way, a thief has to break open and cut apart the lock switchunit in order to determine the true nature of the electrical circuitry.

In the present instance, seven No. 26 electrical wires are justsuficient to accommodate the current load between the primary coil 17and the distributor 12. Any less than seven of the wires 60 or 61 wouldbe less than adequate to carry the load and probably less than fivethereof would be insufficient to sustain engine ignition. It will benoted that the wire 60, 61 and 62 are indistinguishable from one anotherin size and appearance. The wires 60 are connected at their terminaljunction within the connector 56 to a lead 63 that extends from thejunction to the primary coil 17. Thus, the lock switch unit 10 iselectrically interposed between the primary coil 17 and the distributor12 even through a portion of the circuit from the primary coil 17 to thelock switch unit 10 comprises conductors within the same cable as theconductors 61 extending from the lock switch unit 10 to the distributor12.

In accordance with the invention, ifa thief should cut through thearmored conduit and obtain access to the cable containing the wires 60,61 and 62 and thereafter cut through the cable to expose the cut ends ofthe wires 60, 61 and 62, he would be faced with the problem of matchingeach of the seven wires with one of the seven wires 61. The matching ofany of the wires 60 or 61 with any of the grounded wires 62 would merelyserve to ground the ignition circuit and prevent the sustaining ofignition.

Where the automobile security system of the invention is interconnectedin the engine starter circuit rather than in the engine ignition circuitas illustrated in the drawings, one group of conductors (e.g.. 60 or 61)is connected to a terminal on the starter solenoid and another group(e.g., 60 or 61) is connected to an existing lead to the appropriateterminal in the ignition and starter switch unit inside the vehicle.Since the starter circuit is normally adapted to carry a load as high as35 amps, the individual conductors 60, 61 and 62 of the cable assemblyand preferably No. 26 size copper wire insulated as before with a resincoating. In this instance, the lock switch unit 10 disables the startercircuit rather than the ignition circuit.

FIG. 7 best illustrates one example of the result of an attempt by athief to short circuit the lock switch unit from within the vehicle. Asdescribed above with respect to FIG. 7, it will be seen that one of thewire 61 has been grounded, two have been connected to one another andonly two have been connected to the wires 60. The two connections wouldnot provide sufficient current carrying capacity to handle the loadbetween the primary coil 17 and distributor l2 necessary to sustainignition. Furthermore, one of the wires 60 has been connected to groundand this would further aid in defeating attempts to sustain engineignition.

Thus, the unique conductor arrangement embodied in the security systemof the invention substantially reduces the chances that a thief couldsteal the vehicle in which the lock switch unit 10 and associatedequipment are installed.

While the invention has been shown and described with reference to aspecific embodiment thereof, this is for the purpose ofillustrationrather than limitation and other variations and modifications will beapparent to those skilled in the art upon a reading of the specificationand claims. Accordingly, the patent is not to be limited in scope andeffect to the specific embodiment shown and described herein nor in anyway that is inconsistent with the extent to which the progress in theart has been advanced by the invention.

We claim:

1. In a security system for a motor vehicle electrical circuit includinga lock switch assembly electrically connected between two essentialcircuit elements of said circuit. the improvement which comprises acable consisting of a plurality of discrete identical insulatedconductors including a first group connected between one of saidessential circuit elements and said lock switch, a second groupconnected between the other of said essential circuit elements and saidlock switch. and a third group connected to ground whereby if said cableis cut the conductors of said groups are indistinguishable from oneanother.

2. Apparatus as defined in claim 1 wherein said first and second groupscomprises an equal number of conductors, wherein less than said numberof conductors would have insufficient combined current carrying capacity to provide adequate current between said essential circuitelements to operate said engine. and wherein any attempt to complete acircuit with even one wire from the third group will ground the system.

3. Apparatus as defined in claim 2 wherein said first and second groupseach comprises seven conductors and wherein said third group comprisesat least seven conductors.

4. Apparatus as defined in claim 1 wherein said lock switch assembly isencased within a sealed housing defining an enclosed chamber, whereinsaid first and second groups of conductors are wrapped around the wallsof said enclosed chamber at least one convolution, wherein said thirdgroup is bundled inside said housing making it impossible to put it out,and all of said conductors are embedded in an electrical pottingcompound so that any attempt to cut the housing will also out such wiresand make engine operation impossible.

5. Apparatus as defined in claim 1 wherein said essential circuitelements comprise the primary coil and distributor of the engineignition circuit.

6. Apparatus as defined in claim 1 wherein said essential circuitelements comprise the engine starter and the actuating switch therefor.

1. In a security system for a motor vehicle electrical circuit includinga lock switch assembly electrically connected between two essentialcircuit elements of said circuit, the improvement which comprises acable consisting of a plurality of discrete identical insulatedconductors including a first group connected between one of saidessential circuit elements and said lock switch, a second groupconnected between the other of said essential circuit elements and saidlock switch, and a third group connected to ground whereby if said cableis cut the conductors of said groups are indistinguishable from oneanother.
 2. Apparatus as defined in claim 1 wherein said first andsecond groups comprises an equal number of conductors, wherein less thansaid number of conductors would have insufficient combined currentcarrying capacity to provide adequate current between said essentialcircuit elements to operate said engine, and wherein any attempt tocomplete a circuit with even one wire from the third group will groundthe system.
 3. Apparatus as defined in claim 2 wherein said first andsecond groups each comprises seven conductors and wherein said thirdgroup comprises at least seven conductors.
 4. Apparatus as defined inclaim 1 wherein said lock switch assembly is encased within a sealedhousing defining an enclosed chamber, wherein said first and secondgroups of conductors are wrapped around the walls of said enclosedchamber at least one convolution, wherein said third group is bundledinside said housing making it impossible to put it out, and all of saidconductors are embedded in an electrical potting compound so that anyattempt to cut the housing will also cut such wires and make engineoperation impossible.
 5. Apparatus as defined in claim 1 wherein saidessential circuit elements comprise the primary coil and distributor ofthe engine ignition circuit.
 6. Apparatus as defined in claim 1 whereinsaid essential circuit elements comprise the engine starter and theactuating switch therefor.